Powder metallurgy composite

ABSTRACT

A bi-metallic powder metal compact is formed by filling a die cavity with at least two different kinds of metal powder separated by divider means which are then withdrawn from the die cavity so that the powders in the cavity may be compacted in the usual manner. One or a plurality of mated bottom punches fill the cavity until a shoe, which is fed from an external source, carrying the separated different kinds of powder is correctly positioned above the cavity. The punches are then withdrawn to the same or different depths as desired, and the shoe is then removed so that the powders may be compressed in the cavity by a top punch and by said bottom punches.

United States Patent 1191 1111 3,859,016 McGee et al. Jan. 7, 1975 POWDER METALLURGY COMPOSITE 2,337,550 12/1943 Crosby .1 425/130 x 1751 Sherwood McGee, Lisle; James 5223633 @1132? 2312271.... jjjjjjjjijj...iii3ii Mlkoda, West Chlcagoi both Of 3,606,633 9/1971 Engclmann 425/456 x [73] Assignee: AMSTED Industries Incorporated, Primary Examiner-Robert L. Spicer, Jr.

Chicago, Ill.

[22] Filed: Apr. 6, 1973 ABSTRACT {211 A 34 646 A bi-metallic powder metal compact is formed by filling a die cavity with at least two different kinds of metal powder separated by divider means which are [52] US. Cl 425/78, 425/130, 425/456, h withdrawn f the die cavity 30 that the 425/502, 425/517, 425/518, 425/5 ders in the cavity may be compacted in the usual man- {51} hit. Ci B22f 7/02 o or a plurality f mated bottom punchcs fill [58 F'eld of Search 425/502 5181 the cavity until a shoe, which is fed from an external 425/520 456 source, carrying the separated different kinds of powder is correctly positioned above the cavity, The [56] References cued punches are then withdrawn to the same or different UNITED STATES PATENTS depths as desired, and the shoe is then removed so 1,547,260 7/1925 Nighthart 425/130 that the Powders y be Compressed in the Cavily y 2,007,961 7/l935 1 Bolton 1 425/130 a top punch and by said bottom punches. 2,208,054 7/1940 Reed 1 1 425/130 2,218,196 10/1940 Hagar 425/130 x 5 Claims, 14 Drawing Figures POWDER METALLURGY COMPOSITE This invention relates to the production of bi-metallic powdered metal compacts wherein different parts of the compact are formed of metals having different characteristics or are formed of different metals which will sinter together during a heating process which follows compaction of the powdered metal in a die.

A primary object of the invention is to devise simple and inexpensive means and a process for forming such compacts.

A more specific object of the invention is to devise simple and effective removeable means for maintaining the different powders separated from each other in a shoe and in a die cavity into which the powders pass from the shoe.

Another object of the invention is to achieve greater compaction of one type of powder in the die cavity than another type of powder therein.

A more specific object of the invention is to achieve the foregoing objectives while maintaining advantages of conventional equipment such as vibrator shaker means which vibrates the shoe to settle the powders in the die cavity to completely fill the same while preventing mixing of the different kinds of powder by such vibration or shaking.

The foregoing and other objects and advantages of the invention will become apparent from the following specification and the accompanying drawings wherein:

FIG. 1 is a central vertical sectional view of apparatus embodying a preferred form of the invention, portions of the structure being shown in elevation;

FIG. 2 is a view similar to FIG. 1 showing the die cavity filled with separated metal powders having different characteristics;

FIGS. 3 and 4 are views taken on lines 33 of FIG. 2 and 44 of FIG. 1, respectively;

FIG. 5 is a bottom plan view of the shoe shown in FIGS. 1 and 2;

FIG. 6 is a bottom plan view of a modified shoe and;

FIGS. 7-14 are schematic views showing how the apparatus of FIGS. 1-7 may be used to compact one type of powder in a die cavity to a greater extent than another type of powder in the same cavity.

Describing the invention in detail and referring first to FIGS. l-5, the invention will be described with reference to a press having a conventional die 10 with a die cavity 12 containing a pair of bottom punches l4 and 16 supported by a power-actuated platen 18. In such an arrangement the punches 14 and 16 function as a single punch. As hereinafter discussed the punches l4 and 16 may be separately actuated.

The device is shown in FIG. 1 in stripped position with the tops of the punches l4 and 16 flush with the top surface of die 10 and with a shoe 20 slideably moveable along said top surface to a position above said die, as shown in FIG. 1, to start the fill sequence hereinafter described.

The shoe 20 is fed with powders from an external source and comprises a conventional wiper 22 (FIGS. 1, 2 & 5) engageable with the top surface of the die to afford a sealed wiping arrangement therewith to prevent leakage of powder from an internal cavity 24 of the shoe. The shoe comprises a central transverse slot 26 within which a divider blade or plate 28 is snugly but slideably fitted to divide cavity 24 into spaced portions which are fillable through openings 30 and 32 with powdered metal of different characteristics, as for example powdered steel through opening 30 and powdered copper through 32, or austenitic steel through opening 30 and carbon steel through opening 32, or any other desired combination.

The blade 28 is connected to spaced clevis legs 34 by a shaft or pin 3 journalled in complementary openings of said legs and carrying a ball bearing assembly 38 rollingly supported in a complementary slot 40 (FIG. 3) of the blade for a purpose hereinafter described. The clevis is connected to a piston rod 42 of a piston 44 within a conventional air or hydraulic cylinder 46 supported by a standard or column 48 attached to the top of the shoe 20. The standard 48 carries a limit switch 49 for a purpose hereinafter described.

With the parts as shown in FIG. 1, and the cylinder 46 pressurized above piston 44 to hold the blade 26 tightly against the top of punches 14 and 16 the punches are moved downwardly to the position shown in FIG. 2, and the blade 28 follows them (while tightly held against them) to the position shown in FIG. 2. The cylinder 46 is then pressurized below the piston 44 to retract the blade 28 until clevis leg 34 engages the switch 49 at a position whereat the lower edge of blade 28 is slightly above the top surface of die 10 whereupon the shoe 20 and attached parts are slideably moved along the die 10 to a position remote from the cavity 12 so that a top punch (not shown in FIGS. 1 and 2) which snugly fits the top of the cavity may enter it under pressure to compact the powders in the die cavity against the bottom punches 14 and 16, thereby forming a bi-metallic compact in the cavity 12.

FIG. 4 shows the configuration of the die cavity 12 in top plan view, but it will be apparent that other shapes are possible, one variant being indicated by dotted lines at 50.

FIG. 6 shows a modification of the shoe 20 wherein the shoe may be vibrated back and forth as indicated by the arrow in FIG. 4. Under these conditions, the blade 28 is fixed in the die cavity 12, but the shoe 20 may be thus vibrated to facilitate filling of the die cavity with the parts in the position of FIG. 2. This vibratory action of the shoe is accommodated by the ball bearing 38 and slot 40 connection between the clevis 34, 34 and the blade 28 because the cylinder 46 and its piston 44, being attached to the shoe, vibrate with it as permitted by the ball bearing 38. Also, as shown in FIG. 6, this vibratory action is accommodated by spring-pressed plugs 50 mounted in the shoe 20 and engaged with opposite sides of the blade 28 from top to bottom of the shoe 20 thereby keeping the powders at opposite sides of the blade from mixing while the blade 28 remains fixed in the die cavity 12 as the shoe 20 and its attached parts including the cylinder 46 vibrate back and forth as indicated by the arrow in FIG. 4, so that the springs 52 at opposite edges of the blade are alternately compressed and released by such vibration.

After such vibration has continued long enough to ensure proper filling of the die cavity, the vibration is terminated, the blade 28 is raised and the compact is formed as heretofore described.

FIGS. 7-14 are a series of schematics illustrating various steps performed by apparatus such as that shown in FIGS. l-6 except that the bottom punches l4 and 16 are actuated by independent power-operated platens (not shown). In FIG. 7, the upper ends of punches l4 and 16 are flush with the top surface of die 10 thereby completely filling its cavity. A top punch 54 is held in inoperative position, while the shoe 20, as shown in FIG. 8, is slideably moved along the top surface of die to the position of FIG. 8, whereupon the bottom punches 14 and 16 are lowered to the position of FIG. 9 to fill the die cavity 12 with the different kinds of powder at opposite sides of the blade 28, the powder at the right side of the blade as shown in FIG. 9 extending to a greater depth in the cavity 12 because that powder is to be subjected to greater compaction than the powder at the left side of the blade.

The blade 28 is then elevatedto the position of FIG. 10. whereupon the shoe is slideably moved along the top surface of the die 10 to expose the powders in the die cavity as shown in FIG. 11, whereupon the top punch 54 is actuated downwardly and the bottom punches l4 and 16 are actuated upwardly as shown in FIG. 12 whereat the upper ends of the bottom punches are at approximately the same depth in the die cavity 12 to form a bi-metallic powdered compact of substantially uniform thickness.

The die 10 is then moved downwardly as shown in FIG. 13 to expose the bi-metallic compact seated on top of the bottom punches 14 and 16 at a position once again approximately flush with the top surface of the die 10, whereupon the top punch is retracted upwardly to inoperative position, and the compact is removed preparatory to start of a new cycle from the position of FIGS. 7 and 14.

What is claimed is:

1. In apparatus for producing a bi-metallic powdered metal compact; the combination of a die with a cavity extending therethrough, punch means closing the bottom of said cavity, a hollow shoe fed with powders from an external source slideably seated on the die above the cavity, a blade mounted in the shoe for movement toward and away from said punch means, said blade dividing the interior of said shoe into spaced compartments containing, respectively, metallic powders having different characteristics, actuating means mounted on the shoe for moving the blade toward the punch means into tight engagement therewith as the punch means are retracted from the cavity to permit the powders to enter the cavity at opposite sides of the blade, said blade snugly engaging opposite sides of the cavity to prevent mixing of the powders entering the cavity,

and actuating means mounted on the shoe for retracting the blade from said cavity after the powders have entered the cavity, said shoe being moveable in a direction parallel to the plane of the blade from said cavity with the blade retracted to accommodate compression of the powders in said cavity against said punch means.

2. Apparatus according to claim 1 wherein means are provided for vibrating the shoe parallel to the plane of the blade while the blade is in said cavity engaging said punch means, and wherein resiliently mounted plugs snugly fitted in side walls of the shoe from top to bottom thereof engage opposite edges, respectively, of the blade to accommodate such vibration.

3. Apparatus according to claim 1, wherein the blade actuating means are characterized by a power cylinder device having a piston pin, and wherein means are connected to the pin and the blade for accommodating movement of the device parallel to the plane of the blade, and wherein means are provided for accommodating movement of the shoe parallel to said plane without disengaging the blade from the shoe or the die.

4. Apparatus according to claim 1, wherein the punch means comprises separate punches engaging the blade and snugly fitted against each other and against the perimeter of said cavity and wherein one punch is urged further into the cavity relative to the other during compression of the powders to afford differential compression of the respective powders.

5. In apparatus for producing a bi-metallic powdered metal compact, the combination of means for inserting punch means into one end of a die cavity open at the opposite end thereof, means for inserting a divider into said opposite end and for engaging said punch means and for dividing the cavity into spaced compartments, loading means for loading respective compartments from said open end with metal powder having different characteristics, means for retracting the divider from said opposite end of the cavity, means for moving said loading means in a direction parallel to the plane of the divider to clear said opposite end of said cavity and means for inserting another punch means into said opposite end of the cavity and means for compressing said powder in said cavity between the first-mentioned punch means and the second-mentioned punch means. =l 

1. In apparatus for producing a bi-metallic powdered metal compact; the combination of a die with a cavity extending therethrough, punch means closing the bottom of said cavity, a hollow shoe fed with powders from an external source slideably seated on the die above the cavity, a blade mounted in the shoe for movement toward and away from said punch means, said blade dividing the interior of said shoe into spaced compartments containing, respectively, metallic powders having different characteristics, actuating means mounted on the shoe for moving the blade toward the punch means into tight engagement therewith as the punch means are retracted from the cavity to permit the powders to enter the cavity at opposite sides of the blade, said blade snugly engaging opposite sides of the cavity to prevent mixing of the powders entering the cavity, and actuating means mounted on the shoe for retracting the blade from said cavity after the powders have entered the cavity, said shoe being moveable in a direction parallel to the plane of the blade from said cavity with the blade retracted to accommodate compression of the powders in said cavity against said punch means.
 2. Apparatus according to claim 1 wherein means are provided for vibrating the shoe parallel to the plane of the blade while the blade is in said cavity engaging said punch means, and wherein resiliently mounted plugs snugly fitted in side walls of the shoe from top to bottom thereof engage opposite edges, respectively, of the blade to accommodate such vibration.
 3. Apparatus according to claim 1, wherein the blade actuating means are characterized by a power cylinder device having a piston pin, and wherein means are connected to the pin and the blade for accommodating movement of the device parallel to the plane of the blade, and wherein means are provided for accommodating movement of the shoe parallel to said plane without disengaging the blade from the shoe or the die.
 4. Apparatus according to claim 1, wherein the punch means comprises separate punches engaging the blade and snugly fitted against each other and against the perimeter of said cavity and wherein one punch is urged further into the cavity relative to the other during compression of the powders to afford differential compression of the respective powders.
 5. In apparatus for producing a bi-metallic powdered metal compact, the combination of means for inserting punch means into one end of a die cavity open at the opposite end thereof, means for inserting a divider into said opposite end and for engaging said punch means and for dividing the cavity into spaced compartments, loading means for loading respective compartments from said open end with metal powder having different characteristics, means for retracting the divider from said opposite end of the cavity, means for moving said loading means in a direction parallel to the plane of the divider to clear said opposite end of said cavity and means for inserting another punch means into said opposite end of the cavity and means for compressing said powder in said cavity between the first-mentioned punch means and the second-mentioned punch means. 